Signature plays a vital role in our life and the same holds good for machine too.
Practically No machine leaves the work with just the intended operation, but in addition it leaves some distinct mark/s on the work, most of the time they are ignored because, scales at which they occur are beyond the possibility of measurement or to consider.
The signature changes from machine to machine and the signature of a single machine on all the work pieces undergoing same operation will be the same/similar, the signature of machine will exist until the next operation is done on the machine, even then the signature will be transformed into the signature of the machine doing latest operation on the work piece.
These are called machine’s finger prints or signatures which are unique for a machine like the fingerprints of human being. This unique phenomenon is not just limited to machine world but shows its traces in fields like history, psychology, medicine, genetics, computers, botany and zoology.
If I consider a human brain as system a mental shock caused during childhood will have considerable impact on the future actions and we can say the actions are driven by previous shock (May it be a physical or psychological) Similarly in computers, software stored in the system once leaves its traces on the registry any attempt to change it will result in overwriting on the previous signature but not quite really erased.
We may change the dimensional requirements, but cannot change the signature of machine, but its pattern will change with any change in either tool or the maintenance operation is done.
The phenomenon called signature can also be seen as a psychological development in character building which rather defined as the collective effect of multiple influences of persons and their lasting impressions on human mind. Every one you met might have made an impression, some times a lasting and some times not, given the chance to recollect with the correct pulses (trigger) to retrieve it, you may get the actions that were influential in the past. Replications of the reactions to similar experiences may be unobservably small and short term that an observer might not be able to understand without considerable effort.
From the fundamentals of “Deterministic Chaos” a small change in the input data causes large variations in complex scenarios and minimal variations in linear or simple ones.
If we extrapolate our learnings from Machines Signatures to Life , We can understand why we can’t produce perfect clone, or create a perfect life.
Ref: Chaos (a system is chaotic if its trajectory through state space is sensitively dependent on the initial conditions, that is, if unobservably small causes can produce large effects) is the much of use to determine the system and assumptions we are making considering the birth as a linear subsystem.